This invention relates in general to golf clubs and more particularly to golf clubs of the type having iron heads for use on tees and in fairways, with the clubs having improved performance in response to laterally off-set impacts, or mishits, with a golf ball.
As is now well understood, although a golfer controls the swing of a golf club, at the time of impact, the club head acts as if it were a free mass moving at a particular velocity. Most of the energy of this moving mass is imparted to the golf ball in about half of a millisecond, with the result being that the ball, which is compressed against the face of the club, will spring clear as it returns to its normal spherical configuration.
An important factor, among others, involved in achieving ideal impacting of a golf ball is that the point of impact on the face of the golf club head should ideally be below the center of gravity of the head, and when this is achieved, the more a golfer can bet the center of gravity of the club head below the center of gravity of the golf ball, the higher the launch angle and the more solid the hit. Many golf club manufactures in the last decade or so have made it easier for a golfer to achieve this objective by forming the golf club heads with what is normally referred to as "sole weighted club heads". By concentrating a relatively large mass of the golf club head in the sole thereof, the center of gravity of the head is lower than it would be otherwise and this makes it easier for a golfer to get the center of gravity of the golf club head below the center of gravity of the golf ball.
Other important factors involved with ideal impacting of a golf ball are, first, that the impact point on the face of the club head should ideally be in alignment with the center of gravity of the club head and with the center of gravity of the golf ball. And, secondly, the face of the club head should be square, i.e., perpendicular, with the intended travel path of the golf ball. More explicitly, proper alignment is achieved when the center of gravity and the impact point of the golf club head and the center of gravity of the golf ball all lie in a single vertical plane. Therefore, a golf club head is considered to be properly aligned and square when the theoretical plane containing those three points is in alignment with the intended travel path of the golf ball. Deviations from the ideal alignment will result in less than a maximum transfer of energy at the time of impact and deviations in squareness will result in the golf ball deviating to one side or the other of the intended travel path.
The following examples are presented to insure a complete understanding of the above discussed alignment and squareness problems. First consider a situation wherein proper alignment is achieved but the golf club head is not square with the intended flight path of the golf ball. In this situation, a maximum amount of energy will be transmitted to the golf ball but the travel path of the ball will be laterally displaced to one side or the other of the intended flight path. In a second example, consider a situation wherein the club head is square immediately prior to impact but proper alignment is not achieved due to the impact point being laterally offset either toward the toe or the heel of the club head. The amount of energy transferred will be less than maximum resulting in a less than solid hit and a loss of distance. And, the club head will be gyrated, or twisted, to an out of square position as a result of the gyration.
The term gyration, or twisting, are used in here to define a rotation of the club head at the time of impact about an axis which passes through the center of gravity of the club head and is parallel to the axis of the golf club shaft.
It will be appreciated that it can be very difficult even for highly skilled and experienced golfers to achieve perfect alignment and squareness with a high percentage of consistency. Therefore, many golf club manufactures have formed iron golf club heads with relatively large concentrations of mass in the heel and toe of the club head to increase the moment of inertia and thereby maximize energy transfer and resist, or dampen, gyrations resulting from miss-aligned impacting of the golf ball.
Several prior art golf club iron heads have been designed in the general manner discussed above in attempts to achieve optimum gyration dampening characteristics, and the degree of success in achieving this objective varies from one club head design to another. One basic technique used in various ways in several prior art iron golf club heads is to configure the head with a central hollow, or cavity, in the back surface thereof and redistribute the material which would otherwise be in the cavity, in predetermined proportions and predetermined locations on the club heads. Another technique in use is to form relatively smaller cavities in the back surfaces of the club heads, redistribute the cavity material and provide high density weights in predetermined locations in the heel and toe of the club heads.
The gyration dampening characteristics of iron golf club heads depends, along with other design parameters, on the mass of the material that is redistributed or otherwise concentrated in the heel and toe of the club heads, and the specific mass concentration proportions and locations. As mentioned above, the prior art has made several attempts to achieve optimum gyration dampening characteristics.
It would be desirable to provide a new set of golf clubs having iron heads which are configured to provide improved gyration dampening characteristics in comparison to the prior art.